2.1 Quercus section
Quercus section is the only section includes species in both Old
World and New World in this study (Manos et al., 2001). Eleven species
in Quercus section were applied LM and SEM measurements in this
study (Table 2). Variation of sizes, shapes, and surface ornamentation
of pollen in Quercus section is the highest and average pollen
size (Lengths of equatorial axis average 28.22 μm and of polar axis
average 31.92 μm) is the largest in three sections (Table 3 and 4;
Figure 2-6). Pollen shapes tend to be spheroidal. Surface ornamentations
of Quercus pollen include psilate-scabrate, scabrate, and
scabrate-verrucate. The distribution patterns of elements are both dense
and sparse.